According to Thai security officials a series of blasts that killed four people in the last 24 hours across the country are not directly linked to international terrorism.

Thai rescue workers attend to an injured victim after a small bomb exploded in Hua Hin on August 12, 2016.

A string of bomb attacks targeting Thailand's crucial tourism industry that killed four people have been blamed on "local sabotage," officials said on Friday.

Twin bombs exploded in the upscale resort of Hua Hin late Thursday, killing one woman and wounding more than 20 others, including nine foreign tourists. They were followed by two more on Friday morning that killed another person.

A further two blasts struck Friday in the popular tourist town of Phuket, killing one, while two more bombs were reported in the southern provinces of Trang and Surat Thani, again killing a bystander.

Deputy police spokesman Police Colonel Krisana Pattanacharoen told reporters in Bangkok that Police believe the blasts were acts of "local sabotage" and not linked to international militants.

"It's too soon to jump to any conclusion but what we know for sure is that the incidents are not linked directly to any kinds of terrorism, in fact it's local sabotage and we are trying to identify those responsible behind the scenes," Krisana said.

"There are no conflicts in the country that may lead to terrorists being in the country. That's why we can say that these incidents are not terrorist attacks."

Prime Minister Prayut Chan-O-Cha called for calm and said he did not know who was behind the attacks. "The bombs are an attempt to create chaos and confusion," he told reporters. "We should not make people panic more."

"Why the bombs occurred as our country is heading towards stability, a better economy and tourism -- and who did it -- you have to find out for me," he added.

The two bombs that went off in Hua Hin on Thursday evening were hidden in potted plants and went off within 30 minutes of each other in the bar district of the popular beach town.

While small bombings are common in the kingdom during periods of heightened political tension, there have been few such incidents in the past year and it is rare for tourists to be targeted.

Hua Hin is home to the summer palace of Thailand's revered royal family and the blast came on the eve of Queen Sirikit's 84th birthday and just ahead of the first anniversary of a Bangkok shrine bombing that killed 20.

Hua Hin's district chief, Sutthipong Klai-udom, told the AFP that the bombs on Thursday evening were detonated by mobile phone.

According to staff at local hospitals, German, Italian, Dutch and Austrian nationals were among the wounded.

"It was very shocking. There was a loud noise and police were running everywhere; it was terrible," said Michael Edwards, an Australian tourist staying in a guesthouse close to where the second bomb detonated.

"I was just surprised that it happened here... now I'm thinking if it's worth staying," he said.